Pressing apparatus

ABSTRACT

A pressing apparatus for the production of compacted bodies from different powdered materials which are filled layer by layer into a pressing die, is provided with a filling system comprising a plurality of filling frames or shoes which are movable by first driving means in a guideway laterally offset from the filling opening of the die, and by second driving means out of said guideway across the table of the apparatus to the filling opening and back to the guideway.

United States Patent Plocher et al.

PRESSING APPARATUS lnventors: Werner Plocher; Horb Ihlingen;

Franz Kiihl, all of Herdecke', Bernhard Hiittermann, Glinde, all ofGermany Assignees: Jurid Werke GmbH, Glinde;

Maschinenfabrik Lauffer & Butscher, Muhlen, both of Germany Filed: June3, 1974 Appl. No.: 476,148

Foreign Application Priority Data June 6, 1973 Germany 2328700 US. Cl..r 425/257; 425/78; 425/l 30 Int. Cl B30!) 11/02; B30b l5/3O Field ofSearch 425/78, 130, 256, 257,

[ June 3, 1975 [56] References Cited UNITED STATES PATENTS 2,208,0547/l940 Reed 425/130 2,2l8,l96 10/[940 Hagor 425/l30 X 2,552,090 5/l95lEusner 425/[30 X Primary ExaminerJ. Howard Flint, Jr. Attorney, Agent,or Firm-Young & Thompson [57] ABSTRACT 8 Claims, 9 Drawing FiguresPATENTEDJUH3 1975 3,887,317

PRESSING APPARATUS BACKGROUND OF THE INVENTION The invention relates toapparatus for charging pressing dies with several layers of powder-likematerials, particularly for the production of a multi-layer sintercompact, by employing a plurality of charging shoes adapted to betraversed on a table.

For the production of multi-layer sinter compacts the pressing dies mustbe charged with powder materials in consecutive layers. For this purposethe charging shoes which have been filled with the several materialsmust be consecutively traversed over the pressing die in the propersequence, It is also necessary that the several substances shouldsubstantially not intermix during the charging operation.

There are frame type presses known in which the charging shoes are movedto the pressing dies from the back of the press, i.e., the side oppositethat from which the press is controlled. If several charging shoescontaining different materials are to be used the paths of the severalcharging shoes converge at angles which do not exceed 90. In the case ofcolumn presses charging shoes can also be advanced to the die openingfrom the left and right as well as from the back of the press.

Although arrangements of such a kind permitt the several substances thatare to be filled into the pressing die to be kept satisfactorilyseparate they can be used only if the lip of the filling opening of thedie is flush with the press table. Moreover, the spatial requirements ofsuch arrangements are considerable.

Conventional multi-chambered charging shoes permit several materials tobe introduced into pressing moulds although this can be done only in apredetermined and fixed consecutive order. Multi-chamber charging shoesare certainly suitable as such for charging dies having openings withedges or upper surfaces not contained in a plane but in a concave orconvex surface. However, it is impossible without an expenditure whichis no longer acceptable in such cases to keep the substances that are tobe charged separate when multiple chamber charging shoes are used,particularly not when the substances differ in specific gravity.

SUMMARY OF THE INVENTION A main object of the invention consists inproviding apparatus requiring little space for charging pressing dieswith several layers of different powders in such a way that the dies canbe satisfactorily charged even when the upper surface of the charge inthe die in cross section deviates from a straight line.

According to the invention a novel apparatus of the specified kind isprovided with a guideway which is laterally offset from said fillingopening, and with a plurality of charging shoes which are movable onsaid guideway, and of which each one can be coupled for traverse alongsaid guideway to a first drive means and for traverse substantiallyperpendicularly thereto to a second drive means. Furthermore, it is alsoproposed to mount each charging shoe detachably on a baseplate in saidguideway, said baseplate closing the bottom of the shoe in the guideway.According to yet another feature of the invention closing means are alsoprovided for keeping the bottom of each charging shoe closed during itstraverse by the second drive means to the edge of the filling opening.

In a preferred embodiment of the invention the baseplate can be coupledto the second drive means for traversing the charging shoe towards thefilling opening substantially perpendicularly to the guideway.

In yet another desirable embodiment of the invention the tableisprovided in the path of traverse of the charging shoe by the seconddrive means with a table top contour adapted to keep the bottom of thecharging shoe closed during its traverse from the guideway to thefilling opening, the shape of said contour corresponding to thenon-linear cross section or non-linear shape of the edge of the fillingopening.

In apparatus according to the invention the possible number of layers islimited substantially only by the availability of space foraccommodating the necessary hoppers and charging shoes. The severalsubstances can be kept cleanly separated because each substance isconveyed in a separate charging shoe. No commixture in the chargingshoes can therefore occur because each charging shoe is itself chargedonly by a particular hopper with which the shoe is associated.Accordingly, inside the die cavity each layer will be cleanly depositedon the preceding layer. Without difficulty practically any kind of dieused in practice can be filled, irrespectively as to whether the edge ofthe filling opening is concave or convex in any one direction on the topof the press table, because the pressing die can be so disposed that allthe charging shoes are traversed into charging position along the samepath. In the case of conventional dies in which the side walls arerelatively perpendicular the direction of approach will be normal to thenon-linear edge of the filling opening. This principle is alsoapplicable to dies which in plan have the shape of a parallelogram,approach being at one of the parallelogram angles to the edge of theopening which is non-linear. Subject to slight additional aids forsealing the edges of the charging shoes it is also possible to chargedies which have an upper filling surface that defines part of thesurface of a cone.

The principle which underlies the invention resides in slidablydisposing the charging shoes in a row offset from the filling opening ofthe die and in then traversing the shoes out of the two into chargingposition at an angle which depends exclusively upon the shape of thedie.

In the case of frame type presses the guideway for the charging shoes ispreferably located at the rear of the press and the hoppers containingthe several types of powder are preferably also disposed on that sidebut at a higher level.

The first drive means may consist of a chain travelling underneath theguideway and fitted with driving dogs adapted to engage abutment membersattached to the baseplate and projecting downwards through alongitudinal slot in the guideway. Alternatively the baseplates may bedetachably coupled together and the train of baseplates pushed or pulledin intermittent motion along the guideway by pulling or pushing means atone end of the train, one charging shoe at a time being thus advanced toa point where the second drive means is adapted to move this shoe out ofits position in the line towards the filling opening and then back againinto alignment with the rest of the train.

Other aspects and features of the invention will be understood from theclaims and from the following detailed and particular description inconnection with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a simplified part sectionalrepresentation of a column type press using a conventional chargingshoe;

FIG. 2 is a view in plan of the die table of the column type press inFIG. 1, partly in section;

FIGS. 3 and 4 are representations of apparatus according to theinvention analogous to the above representations of conventionalequipment in FIGS. 1 and 2;

FIG. 5 is a perspective view of parts of apparatus according to theinvention and a modified arrangement for traversing the charging shoes;

FIGS. 6 and 7 are end and side views of charging shoes used in apparatusaccording to FIG. 5; and

FIGS. 8 and 9 are a plan and elevational view of the means for crosstraversing the charging shoes.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 theseillustrate the state of the art in the case of a column type presscontaining a die plate 11 and columns 12. The press is equipped with aconventional two-chambered charging device comprising a hopper 13containing two chambers 14 and 15 with bottom pouring tubes 16 and 17and a twochambered charging shoe 18 divided into an upper chamber 19 anda bottom chamber 20. These two chambers 19 and 20 communicate through adrop flap 21 which can be opened to allow a powder to be also dischargedfrom the upper chamber 19. In the drawing two layers A and B of powdermaterials for the production of a two-layer sinter compact have alreadybeen introduced into the open cavity of a pressing die between a bottomram 22 and the wall of an opening 24 through the die table.

The directions in which traverse is possible are indicated by two-headedarrows in FIG. 2. The traversing paths pass between the columns 12 ofthe press from and to the right and the left as well as the back (at thebottom in FIG. 2). In the case of a filling which has an upper surfacethat rises above the die plate, as exemplified in FIG. 1 by theconvexity of the layers A and B, only one of the three possibledirections of movement is actually possible. In the case shown in FIGS.1 and 2 this is from and to the back. If a conventional twochambercharging shoe isused, the difficulty which arises is that the layers ofpowder cannot be deposited in the die cavity so that they have asatisfactorily well defined interface. If more than two layers areneeded. then these difficulties are further accentuated. Moreover, theoperation of filling the charging shoe through the pouring tubes takestime to perform.

FIGS. 3 and 4 illustrate a column press equipped according to thepresent invention, comprising columns 30, a die table 32 containing thedie cavity formed between the walls of an opening 34, a bottom punch 36and an upper punch 38. For charging the die cavity with different powdermaterials in consecutive layers charging shoes 40 are used having abottom face 42 which conforms with the contour of the top of thefilling. The charging shoes 40 are movable in a guideway 50. For thispurpose the charging shoes 40 are mounted on an arrangement 48 ofbaseplates formed with saddles 49 corresponding to the arches 42 forreliably closing the bottom of the charging shoes. The baseplatearrangement 48 may be either an integral part or it may be composed of aplurality of separate baseplates detachably connected together. In theembodiment shown in FIG. 4 the baseplate arrangement 48 and the chargingshoe can be traversed in the guideway 50 in either direction by means ofa hydraulic cylinder which has a piston rod 62 attached at its free endto the system of baseplates 48, as indicated in diagrammatic form inFIG. 4. The hydraulic cylinder 60 is doubleacting and is supplied withpressure fluid through two connections to a valve means 64. The valvemeans 64 also control the pressure fluid supply to a seconddouble-acting cylinder 54 which has a piston rod 56 adapted to push acharging shoe which registers with a gap 52 in the guideway 50 over thedie opening 34 and to retract the shoe into the guideway 50. For thispurpose contour members 44, 46 are provided on the table in front of andbehind the die opening 34. The contour of these members corresponds withthe contour of the saddle members 49 which close the arches 42 in thebottom of the charging shoe 40.

Each charging shoe 40 is associated with a hopper S8 and as soon as itreached a position in the guideway 50 below the associated hopper 58 itis charged with powder from that hopper.

The embodiment in FIG. 5 substantially agrees with that in FIG. 4,excepting that instead of the charging shoes being traversed byhydraulic cylinders, the guideway 50' in the present case is providedwith a central longitudinal slot which accomodates a cable or chain 72provided with driving dogs 74. The cable 72 is driven in eitherdirection by conventional drive means not shown in the drawing. It willalso be understood from FIG. 5 that the contour members 46, 44 may beexchangable members which permit the surface configuration of the dieopening 34 to be varied simply by replacing the members 44, 46. Thechange in the shape of the arches naturally calls for the replacement ofthe saddles 49 in the baseplate system 48 or of the baseplatesthemselves.

FIG. 6 is an end view of a charging shoe 40 mounted on a baseplate whichcan be traversed along the guideway 50' by an abutment member 76projecting from the underside of the baseplate 80 being engaged by adriving dog 74 attached to a cable 72. The baseplate 80 is formed allround with a retaining ledge 86 excepting on one side towards which thecharging shoe can be pushed off the baseplate. The baseplate 80 mayeither rigidly or detachably and flexibly coupled by couplers 88 to thepreceding respectively following baseplates.

For the purpose of pushing the charging shoe 40 off the guideway 50 or50' the leading end of the piston rod 56 is fitted with spring-loadedcatches 57, as shown in FIGS. 8 and 9. The leading end of the piston rod56 can thus enter an open-ended slot 84 formed in a cleat 82 secured tothat side of the charging shoe which faces away from the die opening 34.When the piston rod 56 is retracted the spring catches 57 engage theback of the slotted part of the cleat 82 and are thus able to push thecharging shoe off its guideway 50 and back again into the guideway. Whenthe charging shoe 40 continues its traversing motion to the left in FIG.7 the end of the piston rod automatically slides out of the openendedslot 84 in the cleat.

What we claim is:

1. A pressing apparatus for transforming volumes of powder-like materialinto compacted bodies. comprismg a table,

a die chamber within said table and having a filling opening defined byparts of said table,

compacting means cooperating with said die chamber for compacting thecontents thereof,

guideway means laterally spaced from said filling opening,

a connecting portion on said table between said guideway means and saidfilling opening,

a plurality of charging frames, each frame defining a hollow space andhaving an open top for receiving powder-like material, and an openbottom for the discharge of said material,

first means for moving said frames along said guideway means,

second means for moving said frames out of said guideway means and alongsaid connecting portion on top of said filling opening and back, and

means for closing said bottom opening outside of said filling opening.

2. An apparatus according to claim 1 wherein the means for closing thebottom opening comprises baseplates to which said frames are detachablyconnected.

3. An apparatus according to claim 1 wherein the means for closing, thebottom openings comprise cooperating profile means at the bottom of saidframes, and at the surface of said connecting portion.

4. An apparatus according to claim 3 wherein the surface of the table inprolongation of said connecting portion beyond said filling opening andadjacent to it, is provided with similar profile means as saidconnecting portion.

5. An apparatus according to claim I wherein coupling means are providedfor detachably connecting adjacent frames on said guideway means.

6. An apparatus according to claim 1 wherein the means for closing thebottom comprise baseplates within said guideway means to whichbaseplates said frames are detachably connected, said baseplatescooperating with said first means for moving said frames along saidguideway means.

7. An apparatus according to claim 1 wherein said first means for movingsaid frames comprise chain means underneath said guideway means, dogsmounted on said chainlike means, and means cooperating with said dogsfor transmitting a driving force from said chain-like means to saidframes.

8. An apparatus according'to claim 1, wherein said second means comprisea ram having a free piston end movable in parallel to said connectingportion, cooperating means at said free piston end and each frame fortemporarily connecting said free piston end with a frame.

1. A pressing apparatus for transforming volumes of powder-like materialinto compacted bodies, comprising a table, a die chamber within saidtable and having a filling opening defined by parts of said table,compacting means cooperating with said die chamber for compacting thecontents thereof, guideway means laterally spaced from said fillingopening, a connecting portion on said table between said guideway meansand said filling opening, a plurality of charging frames, each framedefining a hollow space and having an open top for receiving powder-likematerial, and an open bottom for the discharge of said material, firstmeans for moving said frames along said guideway means, second means formoving said frames out of said guideway means and along said connectingportion on top of said filling opening and back, and means for closingsaid bottom opening outside of said filling opening.
 1. A pressingapparatus for transforming volumes of powder-like material intocompacted bodies, comprising a table, a die chamber within said tableand having a filling opening defined by parts of said table, compactingmeans cooperating with said die chamber for compacting the contentsthereof, guideway means laterally spaced from said filling opening, aconnecting portion on said table between said guideway means and saidfilling opening, a plurality of charging frames, each frame defining ahollow space and having an open top for receiving powder-like material,and an open bottom for the discharge of said material, first means formoving said frames along said guideway means, second means for movingsaid frames out of said guideway means and along said connecting portionon top of said filling opening and back, and means for closing saidbottom opening outside of said filling opening.
 2. An apparatusaccording to claim 1 wherein the means for closing the bottom openingcomprises baseplates to which said frames are detachably connected. 3.An apparatus according to claim 1 wherein the means for closing, thebottom openings comprise cooperating profile means at the bottom of saidframes, and at the surface of said connecting portion.
 4. An apparatusaccording to claim 3 wherein the surface of the table in prolongation ofsaid connecting portion beyond said filling opening and adjacent to it,is provided with similar profilE means as said connecting portion.
 5. Anapparatus according to claim 1 wherein coupling means are provided fordetachably connecting adjacent frames on said guideway means.
 6. Anapparatus according to claim 1 wherein the means for closing the bottomcomprise baseplates within said guideway means to which baseplates saidframes are detachably connected, said baseplates cooperating with saidfirst means for moving said frames along said guideway means.
 7. Anapparatus according to claim 1 wherein said first means for moving saidframes comprise chain means underneath said guideway means, dogs mountedon said chainlike means, and means cooperating with said dogs fortransmitting a driving force from said chain-like means to said frames.